EFFECT OF CORONARY-ARTERY DIAMETER IN PATIENTS UNDERGOING CORONARY-BYPASS SURGERY

Background Coronary artery diameter is known to be inversely associate d with perioperative mortality related to coronary artery bypass graft ing (CABG). This association is believed to be responsible for increas ed risk among women and smaller people. However, the associations betw een sex, body size, and coronary size have not been carefully examined because direct information about coronary size is rarely available. A lso, whether sex has an independent effect on vessel size is largely u nknown. Methods and Results Height, weight, sex, age, status at hospit al discharge, and luminal diameter of the midleft anterior descending coronary artery (mid-LAD) were recorded prospectively in 1325 patients undergoing CABG. Small vessel size was associated with substantially increased risk of in-hospital mortality (15.8% for 1.0-mm vessels, 4.6 % for 1.5- to 2.0-mm vessels, and 1.5% for 2.5- to 3.5-mm vessels, P-[ trend]<.001). Vessel size was strongly related to both sex and measure s of body size. In multiple linear regression analysis, vessel size wa s positively correlated with body surface area (P-[trend]<.01), body m ass index (P-[trend]=.004), height (P-[trend]=.001), and weight (P-[tr end]=.001). After controlling for differences in age and body size, se x remained an important predictor of coronary size. Within each quarti le of each body-size measure, mid-LAD diameter in men was greater than that in women (mean difference [range], 0.14 to 0.23 mm). Conclusions Small mid-LAD diameter is associated with substantially increased ris k of in-hospital mortality with CABG. Although body size is correlated with mid-LAD diameter, women have smaller coronary arteries than men after controlling for differences in body size. These findings further support the hypothesis that smaller coronary arteries explain higher perioperative mortality with CABG in women and smaller people.